Issue: alternative glibc version causes problem (version GLIBC_PRIVATE not defined in file ld-linux-x86-64.so.2)

Problem describe and analysis:

Refer to:

• version GLIBC_PRIVATE not defined in file ld-linux-x86-64.so.2 
• Multiple glibc libraries on a single host 
  

Issue: su user core dumped PAM unable to dlopen

Issue: su user core dumped PAM unable to dlopen (/lib64/security/pam_fprintd.so)

Solution:

 authconfig --disablefingerprint --update 

Ubuntu issues

• How To Fix Sub-Process /Usr/Bin/Dpkg Returned An Error Code (1) In Ubuntu   (check method 5)
  

Using Fail2ban To Secure SSHD Service

Refer to 

• How To Protect SSH With Fail2Ban on CentOS 7 
• Linode: Using Fail2ban to Secure Your Server - A Tutorial 
• How to Secure Your Linux Server with fail2ban 
  

If you set a longer ban duration (like several hours), but want to allow an IP address to make another connection request sooner, you can parole it early.

We type the following to do this:

sudo fail2ban-client set sshd unbanip 192.168.5.25

LVM Can't read superblock

Refer to Can't read superblock : mounting error /dev/sda6